In a mobile communication system, a communication terminal such as a mobile telephone can access the Internet by communicating with a base station and via a core network. The communication terminal performs communication via a path (e.g., a bearer) established between the communication terminal and an apparatus (e.g., a gateway) provided in the core network.
A technique for gateway relocation in a mobile communication system as described above is disclosed in Section 5.10.4 of NPL 1. Referring to figure 5.10.4-1 of NPL 1, the gateway via which data is forwarded is switched in response to gateway relocation.
Moreover, PTL 1 discloses a technique in which when the ATM connection is switched, both a rearrangement-source connection and a rearrangement-target connection are retained for a certain period of time, thereby preventing packet loss.
Further, PTL 2 discloses a technique in which in traffic migration between paths with different properties, initiation of the processing for migrating traffic to the migration-target path is triggered by completion of the configuration of the migration-target path, thereby preventing packet loss.